<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>content替换</title>
    <style>
        input[selected="true"]{
            border:3px dashed black;
        }
    </style>
</head>
<body>
<input type="checkbox" selected="true"/>橘子
<input type="checkbox"/>香蕉
<input type="checkbox">苹果
</body>
</html>